---
title: "The measurement problem · Library · Simulation Hypothesis"
url: https://simulation-hypothesis.com/library/measurement-problem
description: "The measurement problem is the open question of how, why and whether the wave function collapses to one definite result when we measure it, and what counts as a measurement."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

## Quantum mechanics

# The measurement problem

Definition

The measurement problem is the open question of how, why and whether the wave function collapses to one definite result when we measure it, and what counts as a measurement.

On this site

The Observation dial takes a render-on-observation view: being watched is what costs computing.

Role in the model

The Observation dial takes the renderer’s side in a dispute that’s still open: being watched is what costs computing. Physicists don’t agree on what observing does to a system. The sandbox doesn’t need them to agree. It only needs a dial.

Related

[Superposition](https://simulation-hypothesis.com/library/superposition)[Observer effect](https://simulation-hypothesis.com/library/observer-effect)[Many-worlds interpretation](https://simulation-hypothesis.com/library/many-worlds)

## The people behind the terms

14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading).

[Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers)